EVALUATION OF THE PAVEMENT STRUCTURAL CONDITION AT NETWORK LEVEL USING FALLING WEIGHT DEFLECTOMETER (FWD) DATA

Large amounts of seal coats and thin overlays are applied every year by state highway agencies to improve the surface condition of pavements, but these measures have not successfully prevented the problem from reoccurring. As a result, the overall pavement condition keeps deteriorating because of the structural deformation of pavement layers and the subgrade. To make effective decisions about the type of treatment needed, the structural condition of a pavement should be taken into consideration. The paper examines several different structural estimators that can be calculated using the FWD data and the available information stored in the Pavement Management Information System (PMIS) at the Texas Department of Transportation (TxDOT). The analysis considers pavement modulus and the Structural Number (SN) as the structural estimators of a pavement. The evaluation methodology is based on the sensitivity of the structural estimators to the deterioration descriptors. The deterioration per Equivalent Single Axle Loads (ESAL) of all major scores stored in the Texas PMIS was introduced as the major indicator of pavement deterioration. In addition, the paper suggests the subsequent use of the Structural Condition Index (SCI) as a screening tool to discriminate between pavements that need structural reinforcement from the ones that do not. Such index is calibrated for use at the network level M&R analysis.